Mammalian cells require a consistent source of oxygen and nutrients to allow them to function normally. When their access to oxygen and nutrients is interrupted, cell damage and death can quickly result. Certain cell types, including muscle cells and neurons are particularly vulnerable to ischemic injury in connection with myocardial infarction and stroke. Despite recent advances in treating ischemic injuries, stroke and myocardial infarction continue to kill or disable vast numbers of people each year. In the United States alone, 600,000 new myocardial infarctions and 320,000 recurrent attacks occur annually. About 38 percent of the people who experience a myocardial infarction in a given year will die, while many of those who survive will experience some loss in cardiac function. Current cell replacement strategies for treating myocardial infarction involving the injection of stem/progenitor cells result in modest improvements in cardiac function, at best. Low levels of engraftment, survival, and cell replacement after injection of adult or embryonic stem cells into the injured left ventricle wall are current issues that reduce the potential effectiveness of cell replacement strategies after myocardial infarction. Moreover, infusion of cultured adult stem/progenitor cells can be accompanied by microembolism and cardiac arrhythmias. Accordingly, improved methods of treating tissue injury, particularly ischemic injuries associated with myocardial infarction, are urgently required.